Bobbin casing retaining means



April 1952 E. URSCHELER 2,594,523

BOBBING CASING RETAINING MEANS Filed Nov. 12, 1946 2 SHEETS-Sl-IEET 1Izzv ezzrbaz Patented Apr. 29, 1952 BOBBIN CASING RETAINING MEANS EmilUrscheler, St. Gallen, Switzerland, assignmto Brutsch & 00., Zurich,Switzerland Application November 12, 1946, SerialNo.'709,266 InSwitzerland February 28, 1946 The present invention relates to bobbincasing retaining means for sewing machines of the type comprising arotary hook or loop taker revolving about an axis and provided with achamber adapted to receive a bobbin case holder. In sewing machines ofthis type it is customary to utilize rotary hooks having either a closedor an open raceway.

In utilizing a rotary hook having open raceway the bobbin case holderlies with play in the chamber provided in the rotary hook and is looselyheld in the open raceway of the hook generally by a hinged plate.

This drawback or defect does not exist when a rotary hook having aclosed raceway is utilized. However, this latter type of rotary hook ismore complicated to make and, therefore, more expensive.

Accordingly the present invention has for an object to provide anarrangement on a sewing arm of the sewing machine of the type referredto above permitting the use of the same bobbin casing with either typeof rotary hook, namely, one with a closed raceway and also one with anopen raceway.

An additional object is to provide dual pivoted means for holding thebobbin casing against rotation in a rotary hook having a closed racewayand for both holding the bobbin casing in the open raceway of a rotaryhook of this type while simultaneously holding the casing againstrotation relative to this latter type of rotary hook.

One preferred embodiment of the invention is illustrated by way ofexample in a sewing ma chine with a free sewing arm in the accompanyingdrawing, in which:

Fig. 1 is a vertical cross-section through the free sewing arm along thelooper axis, embodying a rotary hook having a closed raceway;

Fig. 2 a plan-view of the structure shown in Fig. 1;

Fig. 3 a vertical cross-section analogous to Fig. 1 showing a rotaryhook having an open raceway,

Fig. 4 a plan-view of the structure shown in Fig. 3.

The looper device as shown in the drawing has the rotary hook I, whichis held by means of a sleeve 2, in a hollow shaft 4 rotatably supportedin the free sewing arm 3 of the machine. The sleeve 2 is provided with aprojection 5 which engages with a complementary sleeve 6 fixed in thehollow shaft 4, in such a way that the rotary hook I can be fixed onlyin one definite position in the hollow shaft 4. The two sleeves 2 and 6are connected to each other by a screw I. The

1 Claim. (Cl. 112-181) shaft 4 may be driven byany desired means, suchas a sprocket and chain or gearing,

The bobbin case 8, in which the thread bobbin is located, has on itsperiphery the annular rib 8 which lies in the closed raceway II] of therotary hook I (Figures 1 and 2) or in the open raceway I0 (Figures 3 and4). In the case of the rotary hook with the closed raceway (Figures 1and 2) a ring I9 is removably secured to the open face of the rotaryhook in any suitable manner in order to provide for the insertion of thebobbin case 8 into the raceway II] of the rotary hook.

The bobbin case 8 has a diametrical slot or recess II, in order that itmay be secured against turning when the rotary hook I rotates.

On the casing of the sewing machine, that is, on the wall of the sewingarm there is pivotally mounted a retaining arm I2 which is provided witha nose I3 and also a boss I2 which, when the arm is swung from theposition shown in Figure 1 to the position shown in Figure 3, engagesagainst the bobbin case 8 to hold it in the chamber formed in the rotaryhook I, while the nose I3 enters into the slot or recess II to hold thebobbin case 8 against rotation in the rotary hook I, as shown in Figures3 and 4. A leaf spring I4, fixed on the casing part 3, has two holes I5therein, into either of which a pin IE on the arm I2 can be brought intoengagement in order to keep the arm I2 in either the inoperativeposition of Figs. 1 and 2 or the operative position of Figs. 3 and 4.During the formation of each stitch it is necessary that the needlethread loop pass around the bobbin case 8 and between the case and theboss I2, and accordingly clearance between the boss I2 and the bobbincase is provided, as shown in Fig. 3.

When using a rotary hook with a closed guiding raceway II], theretaining arm I2 remains in the position shown in Figs. 1 and 2. On theother hand rotation resisting arm II, which is pivoted on the wall ofarm 3, has its nose I8 inserted into the slot or recess II to prevent rotation of the bobbin casing.

It is clear, therefore, that with the previously described structure thesewing arm is adapted to interchangeably receive either a rotary hookhaving an open raceway or a rotary hook having a closed raceway. Theposition of the rotary hook is definitely determined because of thecoupling projections on the sleeves 2 and 6. Furthermore. the bobbincasing 8 will be positively prevented from turning relative to therotary hook either by the arm I2 when the rotary hook has an openraceway or by the arm I! when the rotary hook has a closed raceway. Itis clear, therefore, that the arm I 2 has a dual function to retain thebobbin casing in the chamber of the rotary hook and also to prevent itsrotation relative to the rotary hook. The arm I1, 01 course, beingutilized with a rotary hook having a closed raceway merely prevents thebobbin casing from rotating relative to the rotary hook.

What I claim is:

In a sewing machine having a sewing arm, a 10 shaft rotatably supportedin the arm and adapted to alternately receive rotary hooks having openand closed raceways respectively and which in turn are adapted toreceive a bobbin case having a diametral slot therein, means for holdinga bobbin case in either of the rotary hooks against relative rotationtherein and for retaining same in the open raceway hook, said meanscomprising an arm pivoted on the sewing arm and having a nose thereonadapted to engage in the diametral slot in the bobbin case whensupported in the closed raceway, and a retaining arm pivoted on thesewing arm and having a nose adapted to fit in the diametral slot in thebobbin case when supported in the open raceway and a projection thereonforming an abutment to limit axial movement of the bobbin case in therotary hook, and a locking device for holding the retaining arm ineither the disengaged position or engaged with the bobbin case in therotary hock having the open raceway.

EMIL URSCHELER.

REFERENCES CITED The following references are of record in the

